| [Objective]In recent years,with the advent of aging society,the treatment of patients with proximal humerus fractures has been increasing year by year.Due to osteoporotic fractures,complex Neer three or four part fractures account for about 65%,due to bone causes and easy formation of metaphyseal comminution.Fracture,after the reduction of the patella from the medial cortex defect or poor restoration,the use of locking plate combined with medial support screw fixation,through the follow-up of some patients still occurred after the reduction of neck ridge replacement or radial head varus occurred,seriously affecting shoulder function.For the occurrence of such phenomena,it is proposed to seek new technological breakthroughs and whether attempts to adopt a strong internal fixation method can solve the complications.Currently,new biomechanical research support is needed.Because the treatment of proximal humerus fracture with medial column defect has been a hot topic in clinical treatment,there is no uniform standard for treatment.Although the locking plate combined with medial support screw treatment has achieved satisfactory results,there are still deficiencies in the treatment of metaphyseal comminuted fracture.This study will explore the therapeutic effect of proximal tibial prosthesis combined with titanium plate on the proximal humerus fracture through different methods.[Method]Part Ⅰ: The biomechanical properties of the medial column support of the proximal humerus fracture were investigated by in vitro biomechanical experiments using the combined tibial plate of the proximal and lateral tibia.Eighteen man-made synthetic left SAWBONES zygomatic bones were randomly divided into three groups to establish a surgical neck fracture medial column defect model,using the proximal humerus locking plate fixation,according to different fixation methods are divided into the following three groups: A group PHILOS titanium plate support;B A group of PHILOS titanium plates without supporting screws of the inner column and the rear locking titanium plates are combined together;and group C PHILOS titanium plates with supporting screws of the inner column are combined with the locking titanium plate at the rear side.The Bose ElectroForce? 3510 test system was used to perform axial compression,torsion,shear compression,model failure,and fatigue testing on each of the three groups of specimens.Part Ⅱ: Based on the computer three-dimensional finite element analysis method,the biomechanical force of the medial column of the proximal humerus fracture was simulated under the simulated physiology and test conditions using the combined plate of the proximal and distal tibia to analyze the mechanical distribution of different fixation devices under different stress conditions.Firstly,a 64-slice spiral CT scan was performed on a shoulder joint of a normal adult male to obtain a continuous tomography image and DICOM data was derived.Then the DICOM data was imported into Mimicsl 7.0 software,and a 3D geometric model of proximal humerus was generated using computer simulation.The finite element analysis software ANSYS was used to perform meshing and material attribute assignment to generate a finite element model,constraining the boundary conditions,and simulating the physiology and force applied to the proximal and distal tibial plate combined with steel plate to support the biomechanics of the medial column fracture of the proximal humerus fracture.Stress conditions,analysis of stress distribution characteristics.RESULTS: The finite element model was established to simulate shoulder joint experimental condition conditions: an axial load of 600 N was applied to the proximal three-dimensional finite element model of the humerus;the specimen was abruptly rotated at a position of 20° and an axial load of 600 N was also produced to simulate a fall.Shear force on the upper limb;acting on the center of the humeral head for 5 N·M torsional loading.Part Ⅲ: To investigate the therapeutic effect of both minimally combination lateral with posterior locking plates and PHILOS in the treatment for the proximal humerus fractures.Random control 29 cases of patients with proximal humerus fractures,were classified according to Neer classification and included dual plate group 14 casesand PHILOS group 15 cases respectively.We recorded operation time,blood loss volume,bone union rate,humeral neck stem angle and function rehabilitation conditions.[Results]Part Ⅰ: The PHILOS titanium plate support,the joint fixation of the PHILOS titanium plate and the rear locking titanium plate without the supporting screws of the inner column,and the combined fixation of the PHILOS titanium plate with the support screws of the inner column and the rear locking titanium plate Fixing method,in which the maximum axial compression load of the PHILOS titanium plate support group is 177.10±5.1N,and the maximum axial compression load of the joint fixation group of the PHILOS titanium plate without the inner column supporting screws and the rear locking titanium plate is 217.83± The maximum axial compression load of the combined fixation group of PHILOS titanium plates with rear column locking titanium plates with 8.3N,support screws is 249.57±20.5N,P<0.05;the compression stiffness of the PHILOS titanium plate support group is 170.25.±10.3N/mm,PHILOS titanium plate without rear inner column supporting screws and joint locking group of rear locking titanium plates with compression stiffness of 225.49±17.9 N/mm,PHILOS titanium plate with supporting screws for inner column The compression stiffness of the joint fixation group with the rear-locking titanium plate was 245.11±27.5 N/mm,P<0.05;the maximum torque of the PHILOS titanium plate support group in the torsion test was 2.262±0.6 N·m without the inner column.PHILOS titanium plate supporting the screw with rear locking The maximum torque of the torsion test of the titanium plate joint fixation group is 2.675±0.2 N·m.The combined torque of the PHILOS titanium plate with the support screw of the inner column and the rear locking titanium plate is 2.609±0.12 N.m,P<0.05;the maximum load of the shear compression test of the PHILOS titanium plate support group is 86.87±7.7N.The joint fixation group of the PHILOS titanium plate without the inner column supporting screws and the rear locking titanium plate is cut.The maximum load of the compression test was 98.43±9.4 N.The maximum load of the shear compression test of the joint fixation group of the PHILOS titanium plate with the support screw of the medial column and the rear locking titanium plate was 115.43±15.6 N,P<0.05;The compression stiffness of the PHILOS titanium plate support group is 80.79±12.5 N/mm,and the compression stiffness of the joint fixation group of the PHILOS titanium plate without the inner column supporting screws and the rear locking titanium plate is 100.4±14.7 N/mm.The compression stiffness of the joint fixation group of the PHILOS titanium plate with the inner column supporting screws and the rear locking titanium plate was 123.66±20.4 N/mm,P<0.05;the failure load of the PHILOS titanium plate support group model was 790.35±60.8 N.PHILOS titanium plate and rear side without supporting screws for inner column The failure load of the joint fixation group model with locked titanium plate was 1261.23±97.88 N.The failure load of the combined fixation group model of the PHILOS titanium plate with the inner column supporting screws and the locking titanium plate on the back was 1593.7±144.7 N,P<0.05;The difference between the initial and final fatigue tests of the PHILOS titanium plate support group was 0.52±0.12 mm.The displacement difference between the PHILOS titanium plate and the rear locking titanium plate of the joint fixation group without the inner column supporting screw was 0.39 at the beginning and end of the fatigue test.The difference between the initial and final fatigue tests of the joint fixed group of PHILOS titanium plates with rear column locking titanium plates ±0.08 mm with the inner column was 0.21±0.04 mm,P<0.05Part Ⅱ: Finite element experiments showed that the medial cortical bone defect of the proximal tibia was made from a single steel plate compared with the double plate support.The PHILOS titanium plate with the medial column supporting screw was combined with the posterior locking titanium plate,and the supporting screw without the medial column was compared.The combined fixation of the PHILOS titanium plate with the rear locking titanium plate and the axial compressive strength of the pure PHILOS titanium plate support are gradually reduced and there is a statistical difference;the PHILOS titanium plate with the inner column supporting screw and the locking titanium plate on the back side The combined fixation of the PHILOS titanium plate without a medial column supporting screw and the posterior locking titanium plate and the shear strength of the pure PHILOS titanium plate support gradually decreased and there was a statistical difference;with a medial column The combined fixation of the PHILOS titanium plate supporting the screw and the rear locking titanium plate,the joint fixation of the PHILOS titanium plate without the inner column supporting screw and the rear locking titanium plate,and the torsional strength of the support of the pure PHILOS titanium plate are gradually reduced and There are statistical differences.Part Ⅲ: A total of 29 patients were followed up.Followed-up time was 12 months to 16months(mean 13.6months).Significant difference in Neer and Constant score excellent-good rate after followed-up 6months between LPDP and PHILOS group,dual plates was better than PHILOS group(P<0.05).Significant difference in bone union time,LPDP group was better than PHILOS group(P<0.05),but PHILOS group was superior to dual plates group in operation time(P<0.05).No significant difference in blood loss volume of intra-operation and Neer and Constant score after followed-up 12 months both groups(P>0.05).[Conclusions]1.In this experiment,through in vitro biomechanical experiments,the results show that the combined support of the lateral steel plate and the posterior steel plate with the supporting screws of the medial column has the best biomechanical properties and is significantly stronger than the conventional single steel plate support.The combined bracing of the lateral steel plate and the posterior steel plate through the supporting screws with medial column is worthy of clinical application to prevent postoperative internal fixation failure;2.In this experiment,the proximal humerus finite element model was established to simulate the biomechanical stress of the medial column of the proximal humerus in the simulated physiology and test conditions.The combined support of the outer steel plate and the rear steel plate with the supporting screws of the medial column has the best biomechanical properties and is significantly stronger than the conventional single steel plate support.The combined bracing of the lateral steel plate and the posterior steel plate through the supporting screws with medial column is worthy of clinical application to prevent postoperative internal fixation failure;3.Combination lateral with posterior locking plates can steadily fix the proximal communitied and unstable medial calcar humeral fractures,and patients can early exercise motion and get satisfactory function rehabilitation,avoid to occur post operation complication. |
PDF Full Text Request